When you want to lift your four wheel drive up you have two options. The first option is the more common, and is known as a suspension lift. This involves replacing the springs and shock absorbers currently in your vehicle with larger springs and shock absorbers. Most people will get a heavier duty set as well, to cope with driving on uneven terrain for hours at a time. The only issue with this type of lift is that if you go much more than 4 inches, you get a lot of sideways movement, especially when you go around a corner on the road. Your car no longer steers or brakes as well as it used to, and you get considerably more wind resistance.
The alternative then is a body lift. Many people prefer to lift the body and a the suspension, as lifting the body is done with solid blocks (meaning the car will not move sideways because of it). A body lift involves fitting little blocks (usually 2 inch) in between the body and the chassis. The bolts that hold the two together are replaced with longer ones and your car now sits 2 inches higher. The only issue is that everything attached to the chassis stays where it was originally; the radiator, bull bar, rear bar, sidesteps and anything else that was attached. You can move this up too, but it can be a lot of work.
Some vehicles do not require anything to be done after a the lifting of the car's body, but others may. A good combination to go with is a body lift and a suspension lift as you will limit the sway when going around corners. A body lift is much cheaper, but it means you still have the original suspension, which may need replacing anyway.